Donor-Acceptor Cyclopropanes: Activation Enabled by a Single,Vinylogous Acceptor |
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| Authors: | Nils L Ahlburg Oliver Hergert Prof Dr Peter G Jones Prof Dr Daniel B Werz |
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| Institution: | 1. Technische Universität Braunschweig, Institute of Organic Chemistry, Hagenring 30, 38106 Braunschweig, Germany;2. Technische Universität Braunschweig, Institute of Inorganic and Analytical Chemistry, Hagenring 30, 38106 Braunschweig, Germany;3. Albert-Ludwigs-Universität Freiburg, Institute of Organic Chemistry, Albertstraße 21, 79104 Freiburg (Breisgau), Germany |
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| Abstract: | A novel class of highly activated donor-acceptor cyclopropanes bearing only a single, vinylogous acceptor is presented. These strained moieties readily undergo cycloadditions with aldehydes, ketones, thioketones, nitriles, naphth-2-ols and various other substrates to yield the corresponding carbo- and heterocycles. Diastereocontrol can be achieved through the choice of catalyst (Brønsted or Lewis acid). The formation of tetrahydrofurans was shown to be highly enantiospecific when chiral cyclopropanes are employed. A series of mechanistic and kinetic experiments was conducted to elucidate a plausible catalytic cycle and to rationalize the stereochemical outcome. |
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| Keywords: | Cycloaddition Donor-Acceptor Cyclopropanes Kinetics Reaction Mechanisms Tetrahydrofurans |
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